1. Reservation of Copyright
The disclosure of this patent document contains material, which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.
2. Field of the Invention
The present invention relates generally to the field of wireless communications and, in particular, to an automatic antenna directing system capable of accurately pointing a wireless communication directional antenna at a desired transceiver.
3. Description of Background Information
Recent advances in computer and cellular technologies, as well as the unprecedented growth of Internet-related applications, have resulted in placing great demands on conventional communication infrastructures to convey information at high transmission rates with increased reliability. For example, conventional infrastructures were based, at least in part, on statistical telephonic usage patterns. As users progressively spend more time on the Internet and tie up communication lines for longer periods of time, traditional usage patterns are no longer dependable. In many cases, such changes in usage patterns render conventional infrastructures inadequate.
In an effort to meet the demand for high transmission rates and provide users with high-speed Internet access, various wireline and wireless solutions have evolved. Wireline solutions, which include cable network services and Digital Subscriber Line (DSL) services, offer relief to subscribers having access to such services. Because of the relatively high capital expenditures and labor costs associated with providing connectivity and access to new regions, these services are far from ubiquitous.
On the other hand, wireless solutions are more cost effective and may service a wider range of subscribers. These wireless solutions are based on high-speed wireless data communication systems that employ either satellite-based data networks, such as, for example, DirecPC and StarBand services, or terrestrially-based data networks, such as cellular data networks.
Typically, these high-speed wireless data communication systems are power limited hence contemplate the use of a high-gain, narrow beam, highly-directional fixed antenna coupled to a user terminal to deliver information to a subscriber. As such, these fixed user antennas generally manifest stringent alignment requirements. That is, to ensure adequate communication capabilities, the user transmit or receive antennas need to accurately point in the direction of their counterpart antennas for both transmit and receive operations. For example, in high-speed satellite-based data communication systems link budgets have small margins, hence user antennas need to point to a satellite along specific elevation and azimuthal directions in order to maximize the gain of the received beam pattern and, thus, ensure optimal data transmission. Similarly, for high-speed terrestrially-based data communication systems, user antennas need to be aligned along specific elevation and azimuthal directions to point to the radiation center of a cellular antenna arrangement to ensure maximum possible signal-to-noise ratio. It will be appreciated that, although the specific location of both the user antenna and satellite antenna or cellular antenna may be known, such information does little to identify the exact orientation of the user antenna.
With this said, it is to be noted that most fixed antennas are susceptible to misalignment. Various factors, such as, poor initial installation, atmospheric conditions (e.g., wind), and antenna site construction may all contribute to antenna misalignment. Consequently, the misalignment of highly-directional user antennas may have a deleterious effect on the performance of high-speed wireless data communication systems.
Traditionally, the calibration and corrective re-alignment of fixed antennas require the dispatch of a technician to physically adjust the antenna in the direction containing the strongest signal. Such a process is not cost effective and fraught with inaccuracies as technicians often employ a trial-and-error approach to correct misalignments. Moreover, the process is time and task intensive, often requiring several hours of system down time before the misalignment can be corrected. This goes against the normal plug-and-go approach of most of today""s applications.
Systems and methods consistent with the principles of the present invention, as embodied and broadly described herein, provide for an automatic antenna directing system capable of accurately pointing a wireless communication antenna at a desired transceiver.
In one embodiment, the system includes a position location receiver, which receives signals indicating position location information of the antenna and a position location transmitter. A processing mechanism coupled to the position location receiver determines calibration information of the antenna based on the location information of the antenna and the position location transmitter. An alignment mechanism coupled to the processing mechanism and the antenna, automatically orients the antenna, based on the calibration information, and automatically directs the oriented antenna to point to the wireless transceiver, based on the directional location information of the wireless transceiver.
Additional aspects of the present invention include determining the calibration information by first accurately pointing to the position location transmitter via a direction finding mechanism and then establishing a vector reference space. The necessary elevation and azimuthal components, within the vector reference space, are then calculated to identify the proper calibration of the antenna. Once the calibration information has been determined, an alignment mechanism automatically orients the antenna and, based on the directional location information of the wireless transceiver, alignment mechanism automatically directs the oriented antenna to point to the wireless transceiver.